1. Field of the Invention
The present invention relates to a process cartridge, which is detachable from an apparatus body of an electrophotographic image forming apparatus, and to an image forming apparatus using the process cartridge.
2. Description of the Related Art
An image forming apparatus forms an image on a recording medium by using an electrophotographic image forming process. Examples of the image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (a light-emitting diode (LED) printer, a laser beam printer, and the like), an electrophotographic facsimile machine, and an electrophotographic word processor.
Examples of the recording medium, on which an image is formed, include a recording sheet and an over head projector (OHP) sheet (viewgraph).
The process cartridge has such a configuration that at least one of a charging unit, a developing unit, and a cleaning unit, as a processing means, and an electrophotographic photosensitive drum are made into one piece to form a cartridge, which is detachable from the apparatus body. Therefore, the process cartridge also includes such a configuration that at least a developing unit as a processing unit and an electrophotographic photosensitive drum are made into one piece to form a cartridge, which is detachable from the apparatus body.
In the conventional electrophotographic image forming apparatus using the electrophotographic image forming process, such a process cartridge device is adopted that an electrophotographic photosensitive drum and a processing unit for acting on the electrophotographic photosensitive drum are integrally made into a cartridge so as to be detachable from the apparatus body. According to the process cartridge device, a user himself can perform maintenance of the apparatus without help from a service engineer. Therefore, operability can be improved remarkably. For this reason, the process cartridge system is widely used in the field of the electrophotographic image forming apparatus.
In the electrophotographic image forming apparatus, light corresponding to image information, for example, laser light, LED light, or light of a lump, is irradiated onto the electrophotographic photosensitive drum. Accordingly, an electrostatic latent image is formed on the photosensitive drum. Then, the electrostatic latent image is developed by a developing device. Subsequently, thus developed image formed on the photosensitive drum is transferred to a recording medium. Accordingly, an image is formed on a recording medium.
The following structure is known as a guiding structure when the process cartridge is attached to or detached from the apparatus body. The guiding structure is configured such that a first side wall opposite one of side walls of the process cartridge is arranged in a cartridge mounting portion, and first and second apparatus body guides are provided so as to be arranged side by side in a vertical direction, i.e., in the direction of gravitational force, thus allowing the guides to support the one of side walls of the process cartridge. Further, a third apparatus body guide opposite the other side wall of the process cartridge is provided on the cartridge mounting portion to support the other side wall of the process cartridge. With the above structure, inclination of the process cartridge can be avoided when the process cartridge is mounted. Accordingly, the process cartridge can be smoothly mounted into the apparatus body (See Japanese Patent Application Laid-Open No. 2007-219268).